This invention concerns an arrangement for grain transfer and drive connection between a delivery auger in the grain tank of a combine and an external unloading conveyor and, more particularly, for a combine unloading conveyor system in which the unloading conveyor swings between an outwardly and an upwardly inclined normal operating position and an approximately horizontal, inactive position in which the conveyor lies alongside the side of the combine or grain tank.
It is common practice in combine harvesters to deliver grain from the tank by means of a horizontal auger in the bottom of the tank, typically extending transversely and delivering directly to an outwardly and upwardly extending unloading auger conveyor which may include a boot or enlarged housing to receive the grain from the tank. It is also common practice to drive the external unloading auger from the internal delivery auger, the drive connection usually including a bevel gear box. If the bevel gear box is mounted internally at the elbow or angle between the two auger portions, it tends to obstruct the flow of grain; and swinging or pivoting of the external auger about the elbow, between an extended operating position and a retracted or horizontal transport position is not easily arranged.
In a somewhat more practical arrangement, the bevel gear box is moved to the outside of the conveyor channel and one of its drive shafts is made coaxial with the pivot axis of the unloading conveyor portion. The drive connection is completed using suitable jack shaft and drive transfer arrangements, such as a V-belt or chain. West German published patent application No. 2,700,577 (Roderfeld) discloses an example of such an arrangement. Taking a large part of the drive system out of the conveyor channels potentially reduces obstructions to grain flow. However, the accompanying displacement of the pivot axis for the external unloading conveyor results in large relative movement between the fixed and pivoted conveyor portions during pivoting so that a correspondingly large inlet must be maintained in the boot of the unloading conveyor (or a large outlet from the grain tank) to ensure sufficient register to maintain an adequate flow channel at all times. The form of the transition from delivery auger to unloading conveyor thus becomes more bulky and unsightly, with a corresponding increase in cost and weight.